DMR Radios

Discussion of Radios and Communications equipment. Baofeng, Motorola, Icom, Yaesu, It'll all be here one day!
Post Reply
opfor
tactical nylon fetishist
Posts: 204
Joined: Fri Aug 25, 2017 9:19 pm

DMR Radios

Post by opfor » Fri Jul 13, 2018 9:14 am

Patrick got me interested, now I'm reading up...

http://trbo.org/docs/Amateur_Radio_Guide_to_DMR.pdf

Ok, so after reading the attached doc, and going through a bunch of other bits trying to figure it all out. I'm probably re-stating the obvious for some but maybe helping others like myself who had no real fucking clue figure things out...

First: DMR isn't just an encapsulation in the same way P25 is, it's a whole new way of transmitting information (TDMA) this means, there's no possibility of using existing repeater infrastructure to cross over and support DMR.

Second: DMR end-user equipment isn't a be-all-end-all it needs a repeater infrastructure and a great deal of set-up to work.

I've been looking at the Radio Oddity GD-77: https://www.radioddity.com/radioddity-g ... r-mic.html

There are a few different packages and versions available from radiooddity depending on what it comes with, one comes with a programming cable, one with a speaker mic. From a radio perspective, it does support DMR, and encryption with DMR, however it also functions as an analog radio, and unlike most of the P25 units out there, is dual band.

At the moment anyways, moving over to DMR would require either: A) Buying in to the existing infrastructure - i.e. getting a radio ID, and etc from the DMR-MARC, and all the associated overhead, or B) anticipating the purchase of a DMR repeater system (import units seem to be about $1600-1800 and are not portable). I have seen a few people talk about building their own nano-repeaters, however most of these systems seem to transmit in the milliwatt range, which isn't really what most of us would be looking for. I'm not sure if there are any possibilities on the horizon for building smaller more portable units. One site I found listed the following for a "DMR Hot Spot":
Raspberry Pi III Model B with Case : $52.00
DVMEGA UHF Board: $129.00
SMA Antenna : $10.00
Shipping $10.00
Tax: $18.99
Total Cost $219.99
On doing some further digging, it looks like for a local repeater setup (i.e. Not connected to DMR-MARC) you can use analog radios with a discriminator tap. This guy has a pretty good write-up on it:

https://sadigitalradio.com/digital-radi ... -repeater/

I know most of the push so far has been towards using P25, however, this presents some very major hurdles for all of us in the relatively near future: High startup cost, relatively high maintenance costs (batteries, accessories, equipment), lack of frequency agility (this is an ongoing problem), lack of good organization (frequency allocation), and a host of other problems. At the moment, DMR may be a good solution for those of us left off the P25 bus.
OPFOR - Moderator of the Moderated.

dynotronix
mall ninja
Posts: 15
Joined: Sat Oct 07, 2017 6:21 pm

Re: DMR Radios

Post by dynotronix » Wed Jul 25, 2018 2:26 am

Or you could spend fifty to a hundred bucks and get a p25 Motorola HT.

Sent from my Moto G (5) Plus using Tapatalk


opfor
tactical nylon fetishist
Posts: 204
Joined: Fri Aug 25, 2017 9:19 pm

Re: DMR Radios

Post by opfor » Thu Jul 26, 2018 9:10 am

Major downsides to used motorla gear: Sure, the radio is cheap, next I need a battery, a spare battery, a charger, a programming cable, a set of software licenses. At the moment, I'm going to wait for P25 radios and all the associated stuff to come down in price, namely, with more competent gear coming onto the secondary market.

I did end up pulling the trigger on the Radioddity GD-77, it's a dual band radio, came with two antennas, charger, battery and programming cable for ~$60, at the moment, there is much more support for HAM-DMR than there is for much ham P25, programming was a bit of a challenge, but compared to the motorola it was a turn key solution.
OPFOR - Moderator of the Moderated.

dynotronix
mall ninja
Posts: 15
Joined: Sat Oct 07, 2017 6:21 pm

Re: DMR Radios

Post by dynotronix » Thu Jul 26, 2018 4:06 pm

Yeah, but who are you gonna talk to? Licenses?? We done knee no steenken licenses.

Sent from my Moto G (5) Plus using Tapatalk


Post Reply